1. Field of the Invention
The invention relates to a method for the treatment of a semiconductor wafer with a solution containing hydrogen fluoride, and drying and subsequent oxidation of the surface of the semiconductor wafer with an ozone-containing gas.
2. Background Art
A series of cleaning methods have been developed for cleaning semiconductor wafers, e.g. silicon wafers. One of these cleaning methods is based on the treatment of the wafer surface with an aqueous solution of hydrogen fluoride (HF) and subsequently with ozone (O3). During the treatment with HF, the native oxide is removed from the surface. A new oxide layer is thereon formed by the treatment with ozone. Fixedly adhering particles and other impurities can thereby be removed from the wafer surface. The acidic treatment in HF also brings about a very effective removal of metal ions from the wafer surface.
U.S. Pat. No. 5,714,203 describes a method in which a silicon wafer is drawn into an ozone gas atmosphere directly from a liquid tank filled with an HF solution. In this case, the silicon surface is completely freed of the surface oxide in the HF solution, and when the silicon wafer is withdrawn into the ozone atmosphere, the silicon wafer is simultaneously dried and hydrophilized, that is to say that a new oxide layer is produced on the surface. Therefore, the silicon surface outside the liquid tank is always protected by an oxide layer. The method has the disadvantage that it can only be used once or a few times when used within a complete bath cleaning installation with different cleaning solutions, since otherwise the process costs become too high (costs of the additional tanks and cumulative process times). This cost disadvantage becomes even more relevant in the case of silicon wafers having diameters of greater than 300 mm. A further disadvantage is that the undesirable binding of fluorine to the silicon surface occurs in this method. Moreover, this method leads to an increased microroughness and to the formation of haze and light scattering defects (so-called “localized light scatterers”, LLS).